Verizon, the nation's largest wireless company, beat MetroPCS to the courtroom last week. Like MetroPCS, Verizon is asking the U.S. Court of Appeals for the District of Columbia Circuit to hear the challenge, on the grounds that the December 2010 rules retroactively impose new conditions on spectrum the company had leased, and that the FCC overstepped its authority.

"Instead of responding to the public outcry over its walled-garden practices by offering open-internet access services, MetroPCS has chosen to follow the lead of Verizon Wireless and sue the FCC to strike down the commission’s weak, loophole-ridden rules," said Free Press policy counsel M. Chris Riley in an e-mailed statement.

"MetroPCS hopes that by helping to vacate the rules in court, it will be able to continue with its anticonsumer, anticompetitive practices of blocking popular applications like Skype and Netflix unless its subscribers pay a steep ransom."

The FCC's rules are not yet in effect, since they have not been published in the Federal Register. But the companies say that federal court rules seem to say the court challenges related to their licenses need to be filed with 30 days of the FCC's decision, regardless of whether they are in effect or not.